Submission #1302712

#	Time	Username	Problem	Language	Result	Execution time	Memory
1302712		nhmktu	도넛 (JOI14_ho_t3)	C++17	100 / 100	29 ms	1216 KiB

2014_ho_t3

#include <bits/stdc++.h>
#define ll long long
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define ROF(i,a,b) for(int i=a;i>=b;i--)
#define pi pair<int,int>
#define pii pair<int,pi>
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(a) (int) a.size()
#define endl '\n'
#define data "data"

using namespace std;
const ll linf = 1e18;
const int inf = 1e9;
const int MOD = 1e9 + 7, N = 2e5;

void add(int &a, int b)
{
    a += b;
    if(a>=MOD)
        a-=MOD;
    if(a<0)
        a += MOD;
}

int modulo(int x)
{
    if(x<=1)
        return 1;
    return (MOD - MOD/x) * modulo(MOD/x) % MOD;
}

int mul(int a, int b)
{
    return (1ll *a%MOD * b%MOD) % MOD;
}

int n;
int a[N+3];
ll sum;

void inp(void)
{
    cin >> n;
    FOR(i, 1, n)
    {
        cin >> a[i];
        a[i+n] = a[i];
        sum += a[i];
    }
}

bool check(ll lim)
{
    ll sum1 = 0, sum2 = 0;
    int p1 = 0, p2 = 0;
    FOR(i, 0, n - 1)
    {
        while(p1 < p2 && sum1 < lim)
        {
            sum1 += a[p1];
            sum2 -= a[p1];
            ++p1;
        }
        while(p2 < i + n && sum2 < lim)
        {
            sum2 += a[p2];
            ++p2;
        }
        if(sum1 >= lim && sum2 >= lim && sum - sum1 - sum2 >= lim) return 1;
        sum1 -= a[i];
    }
    return 0;
}

void solve(void)
{
    ll l = 1, r = sum / 3;
    ll ans = 0;
    while(l <= r)
    {
        ll m = (l+r) >> 1;
        if(check(m))
        {
            ans = m;
            l = m + 1;
        }
        else
            r = m - 1;
    }
    cout << ans;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    if(fopen(data".inp", "r"))
    {
        freopen(data".inp","r",stdin);
        freopen(data".out","w",stdout);
    }

    inp();
    solve();
    return 0;
}

Compilation message (stderr)

2014_ho_t3.cpp: In function 'int main()':
2014_ho_t3.cpp:104:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |         freopen(data".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
2014_ho_t3.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(data".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 30 / 30
• Subtask 4: 50 / 50